European Herring Gulls in the IJmuiden colony – 2015 breeding season

This year I had the opportunity to lend a helping hand in the gull colony of IJmuiden (Forteiland) in the Netherlands during a full breeding season. This meant visiting the colony each Monday from mid-April to the beginning of July to read rings, count nests and number of eggs per nest, assist with the ringing of adults and juveniles and trying to find out relationships between ringed adults and those between ringed juveniles and ringed adults.

This also allowed plenty of time to take many photos as a way to read rings and (as a private project) to document primary moult and primary patterns.

All in all it was a great way to study Lesser Black-backed Gulls Larus fuscus graellsii (Dutch intergrade) and Herring Gulls Larus argentatus argenteus from up close.

Unfortunately visits to the colony have now come to an end so it is time for some overviews.

First up: Herring Gulls. Those of Lesser Black-backed Gulls will follow later while interesting individuals will follow in separate posts.

All photos were taken during the breeding season of 2015 (from mid-April to early July), all ringed birds have been ringed in the colony.


Female Green YBRB with partner among Lesser Black-backed Gulls. 4 May 2015.

Male Green YBKD. 26 May 2015.

Male Green YBAX incubating 3 eggs. 4 May 2015.

The eggs in the nest of Green YBAX: very dark for a Herring Gull. 11 May 2015.

Young life. 26 May 2015.

Female YBPK near her nest. 29 May 2015.

Male Green YBAJ at the nest with 2 chicks. 15 June 2015.

Male Green YACW. 29 May 2015.

Green YALK. 26 May 2015.

Male Green YBNW with the IJmuiden harbour in the background. 6 July 2015.

Male Green YACW. 29 May 2015.

Female YBCB. 27 April 2015.

Female Green YBAW. 4 May 2105.

Male Green YBJM. It’s in its 9th calendar year but still shows a dark mark on one of the greater primary coverts. 11 May 2015.

Green YBNZ. 11 May 2015.

Male Green YAHS defending its nest. 11 May 2015.

Male Green YBPT with partner Green YBAW. 4 May 2105.

Male Green YBPT with its only chick Green YBZX. 6 July 2015.

The future: Green YBXB shortly after it was fitted with rings. 29 June 2015.

Unfortunately, not all young gulls get the chance to grow up. 6 July 2015.

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